Cibcuit controller



April 13, 1926. I 1,58 1

F. T. FEREDAY CIRCUIT CONTROLLER Original Filed 0 14, 1922 INVENTOR.

A ATTORNEY? Patented Apr. 13, 1926.

UNITED STATES means PATENT OFFICE.

FREDERICK '1. FEREDAY, OF CLINTON HEIGHTS, NEW YORK, ASSIGNOR, BY MESNE ASSIGNMENTS, TO GENERAL RAIL'WAY SIGNAL COMPANY, A CORPORATION OF NEW YORK.

CIR-QUIT CONTROLLER.

App lication filed October 14, Serial No. 594,553. Renewed November' 21, 1925.

To all 'zcimm it may concern:

Be it known that I, FREDERICK T. Fiannnu, a'citizen oi": the United States, residing at Clinton Heights, in the county of Rensselaer and State of New York, have invented certain new and useful Improvements in (lircuit Controllers, of which the following is a specification. i

' My invention relates to controllers for electric circuits. One object of my invention is the provision 01"" a controller the resistance of which at the points of contact in the circuit will remain at a uniform and minimum value for an indefinite period of time. Another object of my invention is the provision of a circuit controller possessing highly desirable characteristics such as permanence of calibration. I will de- Fcribe one form of circuit controller enr bodying my invention, and will then point out the nove "features thereof in claims.

In the accompanying drawing, Fig. 1 is a side elevation showing one form of circuit controller embodying my invention, the

parts being in such positions that the front contact is open and the back contact closed. Fig. 2 is a view similar to Fig. 1, except that the front contact is closed and the back contact open. Fig. 3 is a sectional view on the line 111-111 of Fig. 1.

Similar reference characters refer to similar parts in each of the several views.

Referring first to Fig. 1, the circuit controller comprises an arm 7 of comparatively rigid electro-conducting material which may be ope ated by any suitable means, such 101 example as an electromagnet, or an arm or lever which is actuated either manually or mechanically when a circuit is to be opened or closed, or both. Near its outer end, this arm is provided with two upstanding cars 7 which carry a pivot pin 11. Mounted to rockon this pin is a metallic finger 10, the pivotal point of this linger being intermediate the two ends ofthe finger as shown in Fig. 1. Near its right'hand end the lingcr 10 carries a contact tip 12 which as here shown is rounded, and which may, for example, be a piece of silver wire'attached to the finger by bending, as indicated in Fig. 3. This contact tip 12 co-acts, with a fixed contact member 8 of suitable material such as carbon. The finger 10 is biased to the position-shown inv Fig. 1, with relation" to the arm 7, by means of a spring 13' which spring surrounds a screw 14: mounted in the arm 7. The lower end of the spring 13' bears on the finger 10, whereas the 111 per end of this spring bears against a nut on the screw 1 1. A loclrnut 20 serves to retain the nut 26 in its adjusted position on the screw 14-. Downward movementv ot' the tinger 10 under the influence of spring 13 is limited by a shoulder 39 on the screw 14-. The screw 141- is threaded through suitable hole in arm 7 and passes freely through a hole in finger 10. Thisscrew is locked in suitable position with respect to the arm 7 by a pair ot'nnts 40.

The fixed contact member 8 may be any desired shape and construction. As here shown it consists of a conical shaped piece of carbon which is supported in a tubular shell 8 0t electro-conductire material, the inside of which is likewise conical in formation. 8 designates a screw which is supported in a suitable tired 'inembcr not shown in the drawing. The vertical. position of the carbon contact button 8 may be adjusted by turning the shell 8 on screw 8 and the button 8 locked inadjusted position by any desired means, as for example a loclrnut, 19.

V The circuit controller also comprises a contact member B which may be of any desired construction. As here shown it comprises an arm 7 to the outer. end of which is fixeda tip 9 oi 'silver or other suitable material, which tip co-acts with contact plate 9 attached to a contact spring 15. This spring 15 is made of .high grade non-coiroding spring material sucli as phosphor bronze, and is riveted at 16 to, a comparatively rigid arm 17. he outer or free end of the spring 15 is bent dowmvardly and provided with a slot (1. which receives, with c msiderahle clearance, the adjacent end of the 3.111117, asnore clearly shown in Fig. 3. The spring 15 normally tends to engage thc under surface of the arm 17;that is to say, the normal bias of this spring issuch as to cause the spring to move away from the arm 17 as'tar as permittedby the vertical limits of slot (1. lnother words, spring 15 is assembled with an initial upward trapped pressure. hen the arm '4" is down as shown inFig. 1 so that the contact tip 9? engages the plate 9, the spring 15 willbe depressed until the weight of the arm 7 and the parts attached thereto is balanced. When the arm 7. rises, however, the spring 15 will follow the movement of the arm to an extent limited by the vertical length of slot 64. It will be seen, therefore, that the back contact spring exerts a definite lifting force 011 the arm 7, tending to assist the arm in its upward movement until the spring 15 is arrested by the arm 17. As here shown the arm 17 is bent backwardly on itself and the lower right hand end is attached to a bracket 4:1, which, in turn, is mounted on a fixed support which is not shown in the drawing. An adjusting screw 18, provided with alocknut 18 passes through the lower end of the arm 1? and engages the upper portion of this arm, whereby the exact desired position of the contact spring 15 may be secured during adjust-ment.

As shown in Fig. 1, the arm 7 is in its lowest position so that the front contact is open and the back contact is closed. When the arm? is moved upwardly, the contact tip 12 engages carbon button 8 before the movement of the arm is completed, then during the ensuing motion of the arm the finger 10 is swung on its pivot 11 in clockwise direction, thereby compressing the helical spring 13. hen the arm occupies the upper limit of its stroke, the parts are in the positions shown in Fig.

It will, of course, be understood that the force required to compress spring 13 for a given movement of finger 1O detern'iines the pressure exerted between contact members 12 and 8. The adjustment for the desired contact pressure may be accomplished as follows: The movement of arm 7 after engagement of contact 12-8- being known, it follows of course, that the angular swing of finger 10 around its pivot 11 during such movement is also known. The nut 20 is therefore adjusted on screw 1&- until the opposition olfered by spring 13 to this angular movement of arm 10 balances the pressure desired between the contact members when the contact is closed. The controller is then assembled in the structure with which it is associated, and the carbon button 8 is adjusted by turning shell 8 on screw 89, until contact 12-3 closes atthe proper point. It follows that the subsequent complete move ment of arm 7 will give the desired pressure between the contact members.

One important feature of the construction shown herein is that it does not require any flat phosphor bronze spring stock, and so there is not-hing in the structure to change in position or shape due to internal stresses, temperature changes, etc. Inasmuch as no flat spring stock is used,however, it is necessary to make provision for obtaining the desired contact pressure and this is the function of the helical compression spring 13, which may be proportioned generously for the work it is called upon to .do. I have also found that by virtue of this construction another very desirable characteristic is secured in that the front contact 128 has very low contact resistance. During the closing of the contact there is no appreciable movement of the tip 12 across the face of button 8 after these parts come into engagement the action which takes place at this time being a knuckling or rolling action. In other words, the tip does not slide on carbon 8 but rather rolls thereon. Owing to this operation the point on the carbon button at which the circuit is originally closed is substantially the same as the point which carries the current after the movement of the arm 7 is completed. explained I prefer to make the tip 12 of wire or other cylindrical material because I have found by experience that the knuckling or rolling action is favorable to the maintenance of low contact resistance.

Another feature of the structure is that no bending whatsoever is required for the adjustment of the contact. The adjustment is all accomplished by turning screw 1 1 and positioning nuts 20 and 20 thereon. Any desired amount of pressure may be trapped in spring 13, and a definite compression of this spring can be made to produce the desired contact pressure. As explained hereinbefore, the preferred procedure is to adjust the finger 10 for the desired position and spring pressure before assembling in the electrical device wherein the circuit controller is to be used.

It should be noted particularly that during the process of adjustment no elementor part of the circuit controller is distorted or bent from the condition in which it was brought to the structure prior to assembling, so that no distorting stresses are imposed in the materials which go to make up the structure. It follows that the calibrated adjustment of the structure will not change due to fatigue, temperature changes or other conditions encountered in actual service.

One important feature of the means hereinbefore described for securing the desired contact pressure is that the movement of the coils of spring 13 is comparatively slight with relation to the total length of the material in the spring, and so the distortion is distributed to such a wide extent that it does not have any permanent effect on the mav terial of which the spring is made.

Although I have herein shown and described only one form of circuit controller embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. A circuit controller comprising a movable arm, a screw fixed to said arm and Owing to the action just carrying an adjustable contact finger pivotally mounted on said arm, a spring acting to press one end of said finger toward the arm, an adjustable stop means on said screw for limiting the movement of said finger, and a fixed contact member coacting with said finger near its other end.

2. A circuit controller comprising a movable arm, a contact finger pivotally mounted intermediate its ends on said arm, a spring acting on said finger on one side of the pivotal point to press the finger toward said arm, a support for said spring carrying adj ustable stops for limiting the movement of said finger and for adjusting the tension of said spring, and a fixed contact member 00- acting with said finger on the other side of the pivotal point.

3. A circuit controller comprising a movable arm, a contact finger pivotally mounted intermediate its ends on said arm, means acting on said finger on one side of the pivotal point to bias the finger toward said arm, a stop for limiting the movement of said finger with relation to said arm in response to the action of said biasing means, said biasing means and said stopbeing adjustably mounted on a single support secured to said arm, and a fixed contactmember co-acting with said finger on the other side of the pivotal point.

4;. A circuit controller comprising a movable arm, a contact finger pivotally mounted intermediate its ends on said arm, a screw fixed to said arm and passing freely through a hole in said finger, a coiled spring on said screw actin on said finger to press the latter toward said arm, two nuts 7 on said screw for limiting the movement of said finger toward said arm and for adjusting the tension of said spring, and a fixed contact member co-acting with said finger on the opposite side of the pivotal point from said screw and spring.

5. A circuit controller comprising a movable arm, a contact finger pivotally mounted intermediate its ends on said arm, a screw fixed to said arm and passing freely through a hole in said finger, a coiled spring on said screw one end of which acts on said finger and the other end of which rests against a nut adjustable on said screw, 21 second nut, adjustable on said screw for limiting the movement of said finger, and a fixed contact member co-acting with said finger on the opposite side of the pivotal point from said screw and sprin 6. A circuit controller comprising a movable arm, a contact finger pivotally mounted intermediate its ends on said arm, a screw fixed to said arm and passing freely through a hole in said finger, a coiled spring on said screw one end of which acts on said finger and the other end of which rests against a nut adjustable on said screw, a second nut adjustable on said screw for limiting the movement of said finger relative to said arm in response to the action of said spring, lock nuts on said screw for holding said adjustable nutsrin adjusted positions and a fixed contact member co-acting with said finger on the opposite side of the pivotal point from said screw and'sprin In testimony whereof I aflix my signature.

FREDERICK T. FEREDAY. 

